Well done on your buy - all the things you've mentioned certainly sound as if the car is saveable. The doors from an early MkII with the front quarterlights and the older-style mirrors should also fit and silver is a colour which might turn up if you're patient. Door hinge pins are still available from Volvo and a water pump should be easy to find.
If you want to keep the car original, it's good that everything including the interior is intact, dirty things can be cleaned up

That the nose cone is still solid is great news, they are difficult to source and are usually not in the colour you want
The sunroof might be a pain, be careful how you open it after all this time ... The seal from a VW 1303 / Golf 1 will fit as a direct replacement (search the forum for some more details on that).
If you find the time to post some more pics that'd be great!
Cheers
Tom